1 /* linux/include/linux/clockchips.h
2 *
3 * This file contains the structure definitions for clockchips.
4 *
5 * If you are not a clockchip, or the time of day code, you should
6 * not be including this file!
7 */
8 #ifndef _LINUX_CLOCKCHIPS_H
9 #define _LINUX_CLOCKCHIPS_H
10
11 #ifdef CONFIG_GENERIC_CLOCKEVENTS
12
13 # include <linux/clocksource.h>
14 # include <linux/cpumask.h>
15 # include <linux/ktime.h>
16 # include <linux/notifier.h>
17
18 struct clock_event_device;
19 struct module;
20
21 /* Clock event mode commands for legacy ->set_mode(): OBSOLETE */
22 enum clock_event_mode {
23 CLOCK_EVT_MODE_UNUSED,
24 CLOCK_EVT_MODE_SHUTDOWN,
25 CLOCK_EVT_MODE_PERIODIC,
26 CLOCK_EVT_MODE_ONESHOT,
27 CLOCK_EVT_MODE_RESUME,
28 };
29
30 /*
31 * Possible states of a clock event device.
32 *
33 * DETACHED: Device is not used by clockevents core. Initial state or can be
34 * reached from SHUTDOWN.
35 * SHUTDOWN: Device is powered-off. Can be reached from PERIODIC or ONESHOT.
36 * PERIODIC: Device is programmed to generate events periodically. Can be
37 * reached from DETACHED or SHUTDOWN.
38 * ONESHOT: Device is programmed to generate event only once. Can be reached
39 * from DETACHED or SHUTDOWN.
40 */
41 enum clock_event_state {
42 CLOCK_EVT_STATE_DETACHED,
43 CLOCK_EVT_STATE_SHUTDOWN,
44 CLOCK_EVT_STATE_PERIODIC,
45 CLOCK_EVT_STATE_ONESHOT,
46 };
47
48 /*
49 * Clock event features
50 */
51 # define CLOCK_EVT_FEAT_PERIODIC 0x000001
52 # define CLOCK_EVT_FEAT_ONESHOT 0x000002
53 # define CLOCK_EVT_FEAT_KTIME 0x000004
54
55 /*
56 * x86(64) specific (mis)features:
57 *
58 * - Clockevent source stops in C3 State and needs broadcast support.
59 * - Local APIC timer is used as a dummy device.
60 */
61 # define CLOCK_EVT_FEAT_C3STOP 0x000008
62 # define CLOCK_EVT_FEAT_DUMMY 0x000010
63
64 /*
65 * Core shall set the interrupt affinity dynamically in broadcast mode
66 */
67 # define CLOCK_EVT_FEAT_DYNIRQ 0x000020
68 # define CLOCK_EVT_FEAT_PERCPU 0x000040
69
70 /*
71 * Clockevent device is based on a hrtimer for broadcast
72 */
73 # define CLOCK_EVT_FEAT_HRTIMER 0x000080
74
75 /**
76 * struct clock_event_device - clock event device descriptor
77 * @event_handler: Assigned by the framework to be called by the low
78 * level handler of the event source
79 * @set_next_event: set next event function using a clocksource delta
80 * @set_next_ktime: set next event function using a direct ktime value
81 * @next_event: local storage for the next event in oneshot mode
82 * @max_delta_ns: maximum delta value in ns
83 * @min_delta_ns: minimum delta value in ns
84 * @mult: nanosecond to cycles multiplier
85 * @shift: nanoseconds to cycles divisor (power of two)
86 * @mode: operating mode, relevant only to ->set_mode(), OBSOLETE
87 * @state: current state of the device, assigned by the core code
88 * @features: features
89 * @retries: number of forced programming retries
90 * @set_mode: legacy set mode function, only for modes <= CLOCK_EVT_MODE_RESUME.
91 * @set_state_periodic: switch state to periodic, if !set_mode
92 * @set_state_oneshot: switch state to oneshot, if !set_mode
93 * @set_state_shutdown: switch state to shutdown, if !set_mode
94 * @tick_resume: resume clkevt device, if !set_mode
95 * @broadcast: function to broadcast events
96 * @min_delta_ticks: minimum delta value in ticks stored for reconfiguration
97 * @max_delta_ticks: maximum delta value in ticks stored for reconfiguration
98 * @name: ptr to clock event name
99 * @rating: variable to rate clock event devices
100 * @irq: IRQ number (only for non CPU local devices)
101 * @bound_on: Bound on CPU
102 * @cpumask: cpumask to indicate for which CPUs this device works
103 * @list: list head for the management code
104 * @owner: module reference
105 */
106 struct clock_event_device {
107 void (*event_handler)(struct clock_event_device *);
108 int (*set_next_event)(unsigned long evt, struct clock_event_device *);
109 int (*set_next_ktime)(ktime_t expires, struct clock_event_device *);
110 ktime_t next_event;
111 u64 max_delta_ns;
112 u64 min_delta_ns;
113 u32 mult;
114 u32 shift;
115 enum clock_event_mode mode;
116 enum clock_event_state state;
117 unsigned int features;
118 unsigned long retries;
119
120 /*
121 * State transition callback(s): Only one of the two groups should be
122 * defined:
123 * - set_mode(), only for modes <= CLOCK_EVT_MODE_RESUME.
124 * - set_state_{shutdown|periodic|oneshot}(), tick_resume().
125 */
126 void (*set_mode)(enum clock_event_mode mode, struct clock_event_device *);
127 int (*set_state_periodic)(struct clock_event_device *);
128 int (*set_state_oneshot)(struct clock_event_device *);
129 int (*set_state_shutdown)(struct clock_event_device *);
130 int (*tick_resume)(struct clock_event_device *);
131
132 void (*broadcast)(const struct cpumask *mask);
133 void (*suspend)(struct clock_event_device *);
134 void (*resume)(struct clock_event_device *);
135 unsigned long min_delta_ticks;
136 unsigned long max_delta_ticks;
137
138 const char *name;
139 int rating;
140 int irq;
141 int bound_on;
142 const struct cpumask *cpumask;
143 struct list_head list;
144 struct module *owner;
145 } ____cacheline_aligned;
146
147 /*
148 * Calculate a multiplication factor for scaled math, which is used to convert
149 * nanoseconds based values to clock ticks:
150 *
151 * clock_ticks = (nanoseconds * factor) >> shift.
152 *
153 * div_sc is the rearranged equation to calculate a factor from a given clock
154 * ticks / nanoseconds ratio:
155 *
156 * factor = (clock_ticks << shift) / nanoseconds
157 */
158 static inline unsigned long
div_sc(unsigned long ticks,unsigned long nsec,int shift)159 div_sc(unsigned long ticks, unsigned long nsec, int shift)
160 {
161 u64 tmp = ((u64)ticks) << shift;
162
163 do_div(tmp, nsec);
164
165 return (unsigned long) tmp;
166 }
167
168 /* Clock event layer functions */
169 extern u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt);
170 extern void clockevents_register_device(struct clock_event_device *dev);
171 extern int clockevents_unbind_device(struct clock_event_device *ced, int cpu);
172
173 extern void clockevents_config(struct clock_event_device *dev, u32 freq);
174 extern void clockevents_config_and_register(struct clock_event_device *dev,
175 u32 freq, unsigned long min_delta,
176 unsigned long max_delta);
177
178 extern int clockevents_update_freq(struct clock_event_device *ce, u32 freq);
179
180 static inline void
clockevents_calc_mult_shift(struct clock_event_device * ce,u32 freq,u32 minsec)181 clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 minsec)
182 {
183 return clocks_calc_mult_shift(&ce->mult, &ce->shift, NSEC_PER_SEC, freq, minsec);
184 }
185
186 extern void clockevents_suspend(void);
187 extern void clockevents_resume(void);
188
189 # ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
190 # ifdef CONFIG_ARCH_HAS_TICK_BROADCAST
191 extern void tick_broadcast(const struct cpumask *mask);
192 # else
193 # define tick_broadcast NULL
194 # endif
195 extern int tick_receive_broadcast(void);
196 # endif
197
198 # if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
199 extern void tick_setup_hrtimer_broadcast(void);
200 extern int tick_check_broadcast_expired(void);
201 # else
tick_check_broadcast_expired(void)202 static inline int tick_check_broadcast_expired(void) { return 0; }
tick_setup_hrtimer_broadcast(void)203 static inline void tick_setup_hrtimer_broadcast(void) { }
204 # endif
205
206 extern int clockevents_notify(unsigned long reason, void *arg);
207
208 #else /* !CONFIG_GENERIC_CLOCKEVENTS: */
209
clockevents_suspend(void)210 static inline void clockevents_suspend(void) { }
clockevents_resume(void)211 static inline void clockevents_resume(void) { }
clockevents_notify(unsigned long reason,void * arg)212 static inline int clockevents_notify(unsigned long reason, void *arg) { return 0; }
tick_check_broadcast_expired(void)213 static inline int tick_check_broadcast_expired(void) { return 0; }
tick_setup_hrtimer_broadcast(void)214 static inline void tick_setup_hrtimer_broadcast(void) { }
215
216 #endif /* !CONFIG_GENERIC_CLOCKEVENTS */
217
218 #endif /* _LINUX_CLOCKCHIPS_H */
219